Ab83429

Rumen SCFA concentrations were determined using a gas chromatograph (HP6890N, Agilent Technologies, Wilmington, DE, United States) as described by Yang et al. (2012) (link). Rumen Ni concentration was determined in the supernatant of a 10 ml rumen fluid sample (centrifugation at 900 × g for 5 min) with the atomic absorption spectrometry fitted with a nickel hollow cathode lamp according to the method described by Rahnama and Najafi (2016) . Concentrations of L-lactate, D-lactate, and ammonia, and urease activity were determined by using the L-Lactate Assay Kit, D-Lactate Assay Kit, Ammonia Assay Kit, and Urease Activity Assay Kit (ab65331, ab83429, ab83360, and ab204697, Abcam Trading Co., Ltd., Shanghai, China), respectively, and a microplate reader (Infinite M200 PRO, Tecan Trading AG, Switzerland). SPSS V21.0 (SPSS Inc., Chicago, IL, United States) was applied for statistical comparison using the two-tailed t-test. Differences were considered significant when P < 0.05 in the two-tailed t-test.

Human fatty acid binding protein-2 (IFABP) protein levels (DFBP20; R&D Systems, Minneapolis, USA), human D-lactate (ab83429; Abcam), murine TNF-α (EK282/4-96; MultiSciences, Hangzhou, China), and murine IL-β (KGEMC004; KeyGEN Biotech, Nanjing, China) in plasma were evaluated using commercially available ELISA kits according to the manufacturer’s instructions.

Frozen human plasma samples were thawed at room temperature before detection. In accordance with the manufacturer’s protocol, the colorimetric D-lactate assay kit (ab83429, Abcam) was used to measure D-lactate concentration in the plasma by researchers who were blinded to the group allocations.